Longitudinal beams of a motor vehicle body are typically connected to one another by one or more cross members in the rear region of the vehicle body, e.g., in order to form a closed frame. In this respect, the position of the cross member is varied in the latitudinal direction of the vehicle and adapted to the respective configuration of the motor vehicle or the motor vehicle type. Corresponding modifications of the vehicle body design, particularly with respect to the position of the cross member, may be required depending on whether the motor vehicle needs to be equipped with a trailer hitch or an extendable cargo carrier. This likewise applies a different vehicle types such as, for example, sedans, caravans, station wagons, or limousines.
In order to realize the lowest loading level possible in the trunk region of a vehicle, it is furthermore desirable to arrange the vehicle floor and the bottom trunk lining as low as possible, if applicable even below the level of the longitudinal beams. The cross member needs to be provided at the level of the longitudinal beams for stability reasons and may interfere with the above-described lowering of the cargo floor. In addition, new drive concepts for vehicles, particularly vehicles with hybrid drives or fuel cell drives, require a new layout of the installation space for accommodating the energy storage modules or fuel tanks provided for the respective drive. Particularly in vehicles with hybrid drives or outright electric motor drives, it is desirable to accommodate the required accumulators as low as possible in the vehicle, e.g., in order to improve the position of the center of gravity of the vehicle.
For example, DE 10 2007 047 037 A1 discloses a motor vehicle body with two oppositely arranged rear lateral longitudinal beams, wherein at least one subframe and/or one or more cross members can be assigned to and fixed on the rear lateral longitudinal beams. In this case, the lateral longitudinal beams, the subframe or the cross members are already provided with a number of joints beforehand, wherein these joints are realized and arranged such that one or more correspondingly adapted units and/or attachments can be optionally fixed on the lateral longitudinal beams in the region of the joints in a modular fashion depending on the respectively desired equipment of the motor vehicle rear end.
The design with a plurality of joints, of which only one or a few are actually used for connecting the cross member or the subframe to the lateral longitudinal beams during the final assembly of the motor vehicle body, proves to be complex and cost-intensive with respect to the manufacturing and assembly technology. In addition, the large number of joints provided beforehand increases the vehicle weight.
It is at least one objective to make available a rear cross member of a motor vehicle body that is improved with respect to its weight and installation variability and characterized with respect to its manufacturing and assembly costs, as well as with respect to a reduction of its weight. In this context, at least one aim is to develop a comprehensive vehicle-platform rear cross member structure that can be individually adapted to different vehicle types and equipments. In addition, other objects, desirable features, aims, and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.